Design Of PLC Human-machine Interface And System Software Based On ARM And FPGA

According to independent research that host machine adopts ARM-FPGA structureof the small-sized PLC, the PLC is composed of PLC host, handheld programmer, HMIand other module?each module is connected by CAN bus communicates; in this paper?the HMI, CAN bus communication and PLC host ARM system software will bedesigned?optimized and improved. LPC1768as the main controller of HMI, designhardware and software of HMI, design the mapping relationship between HMI physicalquantity and PLC soft element; research on the methods of constructing the HMIphysical quantity and PLC soft element mapping. Based on further analysis of functionalrequirements of the PLC module, to optimize the design of CAN communicationbetween the various modules. According to the requirements of ARM system of PLChost, design the ARM system software. Finally, the work was carried out to test, whichverify whether meet the design requirements. The main results are as follows:(1) Complete the design of HMI software and hardware. Take LPC1768as the maincontroller of HMI, combine with DWIN intelligent display terminal, configure the CANinterface circuit module and other peripheral circuit module, and design the data storage;establish the mapping relations between physical quantities of HMI and PLC softwarecomponents, when HMI be applied in different object, HMI can establish correspondingrelationship between the physical quantity and the PLC soft element, to solve the generalproblem; complete the communication design, initial design, application design, amongthem, the application design uses the modular design method, achieve HMIcorresponding function.(2) Design and optimize the communication between the each functional modules ofPLC. Complete the overall structure design of CAN communication; improve the CANidentifier design, increase broadcast address, realization of point to multipointcommunication; optimize the CAN protocol, include redefining the meaning makingPLC program data length, CAN communication data format and other, design the CANencoding and decoding.(3) Design the ARM software system. According to the PLC host ARM system usesLPC1768as the main controller, transplant ?C/OS-II operating system, realize multi taskmanagement; through analyzing the PLC host initialization process, design of PLC hostinitialization; redesign the ARM system task priority base on ?C/OS-II operating system.(4) Through the specific examples, test the function of HMI, the transplantation of ?C/OS-II operating system and the accuracy of CAN communication among the PLCeach function module, the test results meet the design requirements.